The discovery of new materials and the development of new methods of making better materials has lead to many new applications in the semiconductor field. These new applications often require different fabrication techniques, particularly as related to smaller size, greater precision in locating various features of the device, adherence of metallic substances to semiconductor surfaces, etc.
A particular example is a device involving compound semiconductors. Various types of devices can be made using compound semiconductors including semiconductor lasers, detectors, light emitting diodes and amplifiers. A typical example is associated with the fabrication and structure of certain microwave semiconductor devices made from various compound semiconductors. Here, minimization of parasitic inductances is critical to good device performance. It permits higher frequency operation and more gain and bandwidth at the high frequencies. Also, more positive attachment of gold to the metal pads ensures good electrical contact and good thermal contact. This permits higher power handling capacity for the device and a higher and more predictable frequency characteristic for the device.
Particularly desirable is a reliable procedure for inducing plating at preselected areas on a compound semiconductor structure. In semiconducting processing, it is highly desirable that this be accomplished without electrical connection to individual devices. In particular, accurate direction of plating processes such as gold plating processes would be highly advantageous in the fabrication of various semiconductor devices. Various references have discussed the deposition of metals on semiconductors including an article entitled "New Semiconductor Contact Technology", by A. B. J. Sullivan, Electronic Letters, Vol. 12, No. 6 (18 March 1976), page 133.